Michelle Victor from the law firm Leigh Day, an expert in food poisoning cases, said: “This is a very rare case of suspected norovirus as it has affected so many people which appear to be connected across a number of sites.

“We are pleased that the PHE have launched an investigation and would hope that this is a wide ranging investigation into the cause which will inform the public as to the source which at this time remains unclear.”

Those affected are advised to call a GP or the 111 helpline if symptoms persist.